The U.N. secretary-general’s special adviser on Myanmar says the resource-rich but desperately poor nation has the potential to become an Asian tiger if it promotes investment, eases financial restrictions, and finds experts to develop the country.

Vijay Nambiar gave an upbeat briefing to a group of reporters Tuesday, ahead of Secretary-General Ban Ki-moon’s visit to Myanmar this weekend, saying that after more than 20 years of “almost self-inflicted hibernation’’ the country has undergone rapid and dramatic political changes.

“I think the pace as well as the nature of the change has been in some ways extraordinary, and perhaps far in advance of what had been envisaged’’ by the military, which ruled the country for 50 years, he said.

Since last year, the new government headed by President Thein Sein has overseen a wave of political reforms and won wide praise for progress toward democratic rule. The government has freed political prisoners, signed truces with rebel groups, and organized April 1 by-elections deemed free and fair that were overwhelmingly won by opposition leader Aung San Suu Kyi’s party and earned the Nobel laureate a seat in parliament after years of repression and house arrest.

“Today, after more than 20 years, Myanmar has a constitution, elections and a parliament,’’ Nambiar said, which despite flaws never happened before.

He said last year’s meeting between Thein Sein and Suu Kyi “has been a major game changer,’’ and he praised the president’s statesmanship and the opposition leader’s agreement to contest the April election despite her opposition to the constitution which was drafted during an era of military rule and gives inordinate power to the military.

Another “game-changer,’’ Nambiar said, was the decision of the 10-member Association of Southeast Asian Nations to choose Myanmar to chair the organization in 2014.